Recovery control in mirrored disks

Abstract

A method for operating a mirrored disk storage system, comprises a determiner component for determining a repair characteristic of a pair of mirrored disks, a comparator for comparing said repair characteristic of a first of said pair with said repair characteristic of a second of said pair, and a cancelling component for cancelling a repair action for said one of said first or said second of said pair that is not selected by said selector.

The invention claimed is: 
     
       1. A method of operating a mirrored disk storage system, comprising the steps of:
 determining a repair characteristic of at least a pair of mirrored disks; 
 comparing said repair characteristic of a first of said pair with said repair characteristic of a second of said pair; and 
 cancelling a repair action for said one of said first or said second of said pair that is not selected by a selector. 
 
     
     
       2. The method of  claim 1 , further including selecting one of said first or said second of said pair having a preferred repair characteristic to be used as a synchronization source disk, wherein said preferred repair characteristic comprises a characteristic that no repair is required for said one of said first or said second of said pair. 
     
     
       3. The method of  claim 2 , wherein said preferred repair characteristic comprises a characteristic that a least repair time is required for said one of said first or said second of said pair. 
     
     
       4. The method of  claim 3 , wherein said preferred repair characteristic comprises a characteristic that no repair is required for said one of said first or said second of said pair and that said one of said first or said second of said pair is a space-efficient copy. 
     
     
       5. The method of  claim 1 , further including detecting that a failure has left read stability in doubt. 
     
     
       6. The method of  claim 1 , further comprising a step of synchronizing said first and said second of said pair using said one of said first or said second of said pair having a preferred repair characteristic as said synchronization source disk. 
     
     
       7. An apparatus for operating a mirrored disk storage system, comprising:
 a determiner component for determining a repair characteristic of a pair of mirrored disks; 
 a comparator for comparing said repair characteristic of a first of said pair with said repair characteristic of a second of said pair; and 
 a cancelling component for cancelling a repair action for said one of said first or said second of said pair that is not selected by a selector. 
 
     
     
       8. The apparatus as claimed in  claim 7 , further comprising a preferred repair characteristic comprising a characteristic that a least repair time is required for said one of said first or said second of said pair. 
     
     
       9. The apparatus as claimed in  claim 8 , wherein said preferred repair characteristic comprises a characteristic that no repair is required for said one of said first or said second of said pair and that said one of said first or said second of said pair is a space-efficient copy. 
     
     
       10. The apparatus as claimed in  claim 7 , further comprising a synchronizing component for synchronizing said first and said second of said pair using said one of said first or said second of said pair having a preferred repair characteristic as a synchronization source disk. 
     
     
       11. A physical computer non-transitory storage medium comprising a computer program product method for operating a mirrored disk storage system, the physical computer non-transitory storage medium comprising:
 computer code for determining a repair characteristic of at least a pair of mirrored disks; 
 computer code for comparing said repair characteristic of a first of said pair with said repair characteristic of a second of said pair; and 
 computer code for cancelling a repair action for said one of said first or said second of said pair that is not selected by a selector. 
 
     
     
       12. The physical computer non-transitory storage medium of  claim 11 , further comprising a preferred repair characteristic comprising a characteristic that a least repair time is required for said one of said first or said second of said pair. 
     
     
       13. The physical computer non-transitory storage medium of  claim 12 , wherein said preferred repair characteristic comprises a characteristic that no repair is required for said one of said first or said second of said pair and that said one of said first or said second of said pair is a space-efficient copy. 
     
     
       14. The physical computer non-transitory storage medium of  claim 11 , further comprising computer code for synchronizing said first and said second of said pair using said one of said first or said second of said pair having a preferred repair characteristic as a synchronization source disk.